Bell-O-Seal Valve


A Large Volume and wide variety of hazardous and toxic material are currently use. Coupled with increasingly stringent regulatory requirements positive containment and control measures have become mandatory.

Bell-O-Seal valves are well qualified to provide technological assistance for applications involving hazardous and difficult-to-handle fluids and gases.

Bell-O-Seal engineers combine more than 15 years of experience in valve design and development with expertise in metallurgical techniques. Their strategic use of stainless steel, Inconel, Monel, Hast alloy and other high performance metals and alloys makes Bell-O-Seal Valves the optimum choice worldwide for a broad range of applications.

The exceptional versatility, superior operating characteristic, robust construction and consistent dependability of Bell-O-Seal Valves have won us widespread acceptance across the industry, especially chemical and hydrocarbon processing industries.

Typical applications of our valves include Thermic fluid, Ammonia, Chlorine, Phosgene, butadiene, Benzene, Ethylene, Hydrochloric acid, Hydrogen, Steam, Fatty acid to name just a fraction of the many possible uses.

Our uniquely engineered, of time and performance tested Bellow Seal valves assure safer operating conditions and compliance with antipollution regulations.

Our ‘Zero Stem ‘Leakage design eliminates product losses, hazards to humans, the environment, and costly downtime required for packing maintenance.

Our Valves are available in all popular sizes in flanged, threaded as well as weld end configurations.

Why Bellow Seal Valves?

One of the most frequent and serious problems valves face is gland leakage, result in wasted and increased plant downtime. Apart from the high cost of energy losses, Gland leakages can also cause serious environmental, ecological and health hazards to plant workers and personnel. Leakage of sensitive material can also constitute to a fire hazard, explosion, or damage to equipment by corrosive material. Air entering the pipeline could produce inflammable explosive or poisonous mixtures. Gland packed valves often demand continual maintenance in accessibility creating particular difficulties. The bellows comply to conditions at high temperatures and are capable of withstanding over 10,000 cycles without failure.

Bellow Seal Design Features:
Design Standards
EN ISO 15761
ASME B 16.34
Bellow Inspections and Test: MSS SP-117
Cycle Life Test is performed with the valve under the pressurized conditions for 10,000 cycles.

Non-Rotating steam prevents torsion of Bellows.

Two Secondary steam Seals:
Steam backseat and stem packing ensure perfect sealing when a bellow is ?????

Long life seating surface:
Stellite 6 faced both seat/disc to prevent seizing and galling.
End Flanged Dimension: ASME B 16.5
Butt Welded End Dimension: ASME B 16.25
Face to Face & End to End : ASME B 16.10
Helium Leak Test is performed for each Bellow assembly using a Helium
Detector with sensitivity of 10-6 std cc/sec.
Multi-ply Bellows: Minimum 2 ply bellows.
Soft Seat Insert on Globe Disc: Soft seat also available for Gas or Vacuum ?????

  1. Maintenance-free globe valve with Bellows sealed stem.
  2. No-leak gland with triple seals: Bellows, Gland packing and seal at full open positions.
  3. No need to tighten or replace gland packing.
  4. Good seal with stellite hardened surfaces on valve plug and valve seat.
  5. Smooth Hand wheel operation.
  6. Durable stainless steel bellows tested to withstand 10,000 cycles.


Material of Construction:

  1. Shell Material: WCB/LCB/CF8/CF8M/CF3/CF3M
  2. Forged Steel:A105/F304/F316/F304L/F316L/LF2/F11/F21
Bellow Material:AISI-316Ti/INCONNEL625/HASTELLOY C276
Our Main products are
Bellow seal Globe valve
Bellow seal Gate valve
Special valves with actuatores
Following are the ratings
ASA 150# 1/2” to 30” : 1/2" to 2" in Forging & 1/2" to 30" in Casting
ASA 300# 1/2” to 30” : 1/2" to 2" in Forging & 1/2" to 30" in Casting
ASA 600# 1/2” to 12” : 1/2" to 2" in Forging & 1/2" to 12" in Casting
ASA 800# 1/2” to 2” in Forging
ASA 1500# 1/2” to 6” : 1/2" to 2" in Forging & 1/2" to 6" in Casting
ASA 2500# 1/2” to 4” : 1/2" to 2" in Forging & 1/2" to 4" in Casting
Primary stem seal? Metallic Bellow Piston ring Gland Packing
Secondary stem seal Gland Packing None None
Stem Leakage Not Possible since Metallic Bellows are designed to last several thousand cycles Occurs as soon as the rings (which are made of gasket mtl) wear out. Very common. Due to friction between stem occurs within a few cycles no matter make valve or quality of gland packing.
Packing Replacement Not applicable Rings need to be changed frequently Packing needs to be replaced very often
Replacement Cost Not applicable Very high High
Media Loss Zero loss. As the isolation is by metallic bellows leakage(in ppm) is not possible Large in case of leaks Considerable amount through gland leakage. Normally large amount when leakage remains unattended.
Equipment downtime Nil Very high for replacing rings Very high for replacing gland packing
Maintenance Cost often Nil High as rings need to be changed at least once in six months Very High. Gland packing needs to be replaced / repacked .This cost along with equipment down time, man hours spent etc. is very high
Valve Life High-in years Low Very Low - in months. Due to leakage through gland, certain parts erode, making the valve irreparable after some months.
Safety Can be used safely for almost any media Can be used for limited media like steam, hot water Highly unsafe when the media is hazardous/poisonous
Cost Comparatively higher initially but lowest total cost of ownership High compared to the benefits viz a viz problems Initially low but very high after some years if cost of packing down time, man-hours spent, number of valves replaced etc. are taken in to account.
Economics of using a Bellow Seal Valve
For analyzing the cost of a Bellow Seal Valve over piston valve or a conventional gate/globe valve we will consider a 15 mm valve operating on STEAM at 150 PSI, in the three types of valves.
1. Bellow Seal Valve.
2. Piston Valve
3. Standard Globe Valve.
A) Capital Cost: We can estimate the cost per unit as follows.
Type Of Valve Cost per valve in US$ I
Bellow Seal valve US$ 75
Piston Valve US$ 38
Standard Globe Valve US$ 20
b) Maintenance Cost: Assuming that gland leakage will begin within a period of 6 months in a standard Globe valve and in a period of 9 months in a Piston valve, then maintenance costs will be as follows.
Type of Valve Cost of Spares Cost of Labour Downtime II
Bellow Seal Nil Nil None
Piston Valve US$ 5 US$ 13 2 Hours
Globe Valve US$ 1.25 US$ 6 1 Hour
Assuming cost of spare piston rings at US 5$ per pair of rings.
Assuming a down time of 2 hours x labour cost of US$ 6 per hour of maintenance.
Assuming cost of gland packing at US$ 1.25
Assuming a downtime of 1 hour x labour cost of US $ 6 6 per hour of maintenance.
C) Cost of downtime & Energy/Media Loss: We will assume a gland clearance of 1 thou (0.001 inches) for estimation of gland leakage and a cost of US$ 20 tone of Steam. Steam will escape at a rate of 25 lbs/hr through this clearance (as per steam tables).
Type of Valve Cost of Spares Cost of loss Media/Engergy III
Bellow Seal Nil None
Piston Valve Priceless us $ 120 per month
Globe Valve Priceless us $ 120 per month
If we assume leakage of 11 kgs / hrs /day =264 kgs (11 kgs * 24 Hrs)of steam loss per day * 30 days = 7920 kgs X steam cost of US$ 20 / Tonne = US$ 160 per month of energy Loss which can be saved !
The cost of down time is priceless and a value as such can be put on it.It can vary from a few hundred to millions of US$ per daycost.?
D) Total cost Ownership (TCO)=I+II+III: So lets estimate that if the leakage is not attended (which is not in most of the plants),the cost of the valve would be as follow.
Type of Valve I II III Total
Bellow Seal US$ 75 Nil Nil US $ 75
Piston Valve US$ 38 US $ 18 US $ 4/DAY (US$ 120/30 DAYS) US $ 55 + US $ 4/DAY
Globe Valve US$ 20 US $ 8 US $ 4/DAY (US$ 120/30 DAYS) US $ 26 + US $ 4/DAY
Total of ownership for a Bellow Sealed of ownership for a Bellow Sealed Valve in 1 year would be: US$ 75
Total cost of ownership for a piston valve in 1 year would be:
US$ 75+US$? 4 /dayx90 days (since we have assumed leakage will begin in 9 months) =US$ 435
Total cost of ownership for a standard Globe valve in 1 year would be US$ 28
=US$ 4/day x 180 days (since we have assumed leakage will begin in 6 months)=US$ 748


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Mumbai - 400 080.

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